Skill 19.5 Connect the chemical and physical properties of elements to electron configuration

Skill 19.5 Connect the chemical and physical properties of elements to electron configuration. 

Nonmetals gain electrons or share electrons to achieve stable configurations and metals lose electrons to achieve them. 

Valence electrons are the electron involved in chemical reactions so let s take a look at the relationship between the valence electron configuration and chemical activity. Remember the octet rule, it seems logical that when there are less than four valence electrons, the atom would want to lose electrons to go back to the previous energy level that was full. And that when the outer energy level is more than half full (more than 4 valence electrons) that the atom would want to gain electrons to complete the valence energy level. 

There are only three electrons in the 3 energy level and the octet rule says there should be eight. Aluminum can try and find 5 more electrons to fill the 3 p orbital or lose the 3s, and 3p electrons. It takes less energy to lose the three electrons (circled), when these electrons are lost an aluminum +3 ion forms with an electron configuration of 1s, 2s, 2p which has a complete octet in the outer shell. 

This information helps us to understand some other characteristics. 

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